Thursday, September 29, 2016

I have been working on a portable Raspberry Pi project for a while - still not there yet but I've completed one important piece.

It's portable so it obviously has a battery. The Pi takes quite a bit of power so it needed to be rechargeable and include a charger. Adafruit make a great device called the PowerBoost 1000C which takes care of the core charging and power supply functions. But I really wanted my project to work like my phone does:

To power it up from a cold state, press a button for a few seconds

To power it off, press the same button for a few seconds

Indicate how much power remains in the battery

Provide an alert when that is running really low

Shut down safely without any data corruption if the battery does run out

To recharge the battery, just plug in a cable from a USB charger

I couldn't find anything that provided all the functionality I wanted - so I built my own

pi_power consists of fairly straightforward circuitry that links the PowerBoost to the Pi in conjunction with two python scripts that run in the background and monitor the battery voltage.

If you are building a portable RasPi project then you might want to take a look

Wednesday, June 8, 2016

Look on Amazon and you will find a variety of cheap USB microscopes. These are basically a USB video camera with a macro lens. They are good for inspecting fine details of things like electronic components, plants, insects, stamps, etc. but they are not powerful enough for looking at, say, cells in biological samples.

I just bought one to help me capture images of various plant pathologies.

They are marketed as having a range of magnification from, for example, 20 to 300X and the cameras have resolutions anywhere from 0.3 to 5 M pixels. Be aware that the specified magnification range may include the magnification inherent in displaying the image on a large monitor !

Dino-Lite make a range of professional USB microscopes of various sorts but these can cost hundreds of dollars. For basic experimentation there are a load of other vendors and products with prices in the $50 - $100 range.

If you look on Amazon it will be obvious that the same basic models are being sold be several different vendors.

And with a different stand, or without a stand, by a wide variety of other vendors

I went with the $60 DBPOWER variant with a 5 MP camera. It comes with the stand in two pieces and a CD containing software called MicroCapturePro for PC and Mac.

You need software to interact with it - it does not just show up as a camera in the MacOS ImageCapture or Preview tools.

I don't have a CD drive on the machine I want to use this with and transferring the software from one that does is a bit of a pain. So I looked online for the software.

You can get MicroCapturePro from Celestron but after digging around a bit I would recommend a different solution.

Plugable have a similar microscope and they provide a piece of software called Digital Viewer - get that and install it on your Mac (they have a Windows version too). When I started it up it displayed the view from my webcam but click the Settings icon in the top left and select the microscope.

The focussing mechanism on these microscopes is a bit rough but you'll get used to it. I can see that I may want to build myself a better stand and illumination rig.

Under Settings you can select the image resolution and do a bit of image adjustment. You can take individual images, videos or a set of timed images.

It looks like it will do exactly what I need it to do - for $60 that's not bad.

Saturday, November 28, 2015

The MagSafe power connector kept falling out of my wife's MacBook Air. I figured it might be due to just wear and tear on the edge of the plug but when I looked at it I could not see any problem.

Last week I took another look at the plug and socket while I was wearning my magnifying reading glasses - and there was the problem !

The MagSafe socket is magnetic and so any metal dust that gets rubbed off from the plug will stick to the magentic surface. As a result you can see dark dust adhering to that. But in addition, there was a small metal shaving that was stuck there as well - large enough to interfere with the plug being properly seated. It was small but 'chunky' enough to cause the problem. No idea where it came from - not from the plug. I removed that with a pairs of tweezers and cleaned up the adhered dush with the end of a slightly damp Q-tip.

Monday, September 22, 2014

I operate the TABS Therapeutic Antibody Database which help biotechnology companies working in the field of antibody development. TABS represents the most comprehensive resource in this field.

With all that data available, I have compiled summary statistics that show the growth of this area of biotech over the years. I have made charts of those trands and have made those freely available on the TABS database site. You can find all the charts HERE.

When you view a video on youtube.com you get not only the video, but a bunch of suggested related videos and often times a lot of comments and other text. All this clutter gets in the way of what you want to do - simply watching the video.

So I wrote TV Eye, a simple service that embeds your desired video in a simple, plain web page, with none of the usual clutter.

To use, go to youtube.com and find the video that you want to watch. Copy the URL for the video and paste it into the form on TV Eye.